Overlapping homologous superfamilies

Family relationships

Description

Transferrins are eukaryotic iron-binding glycoproteins with the ability to bind ferric iron with high affinity in the cleft of each of two homologous lobes. They control the level of free iron in biological fluids [PMID: 3032619]. Members of the family include blood serotransferrin (siderophilin), milk lactotransferrin (lactoferrin), egg white ovotransferrin (conalbumin), membrane-associated melanotransferrin and saxiphilin from the American bullfrog (Lithobates catesbeiana), which binds to the neurotoxin saxitoxin [PMID: 1869567]. Family members that do no bind iron have also been discovered, including inhibitor of carbonic anhydrase (ICA), which strongly binds to and inhibits certain isoforms of carbonic anhydrase [PMID: 20572014].